Water phytoremediation of cadmium and copper using Azolla filiculoides Lam. in a hydroponic system

Abstract

The aim of this work was to evaluate the utility of Azolla filiculoides growing in a hydroponic system for the phytoremediation of continental water polluted with cadmium and copper during 7 days of exposure. Cadmium and copper chloride were added to the medium at concentrations of 0.5–10 mg/L and 0.1–25 mg/L, respectively. Cadmium and copper levels were measured in each plant using flame atomic absorption spectrophotometry. The analytical methodology used to measure cadmium and copper levels was validated with standard reference material (SRM) – 1570 (spinach) National Institute of Standards and Technology. The results indicated that cadmium and copper phytoremediation was statistically significant with a maximum increase in plant tissue of 1623.20 and 6013.1 μg/g, respectively. This photosynthetic efficiency was chronically damaged when Azolla filiculoides were exposed to 10 mg/L of Cd and 25 mg/L of Cu. The Azolla plants were not affected in the other phytoremediation treatments with copper.

TiO2 nanoparticles may alleviate cadmium toxicity in co-treatment experiments on the model hydrophyte Azolla filiculoides

“…In particular, Azolla filiculoides has been chosen due to its high biomass production, metal accumulation ability (Valderrama et al 2013;Naghipour et al 2018) and free floating nature, all positive characteristics for phytoremediation purposes. In addition, the high water content typical of A. filiculoides fronds (Serag et al 2000) drastically reduces the problems of disposal (Sood et al 2012) and its ability to make symbiotic relationship with the heterocystous blue-green alga, Anabaena azollae, allows its growth also in contaminated low nitrogen environment.…”

Influence of Soil Chemistry and Plant Physiology in the Phytoremediation of Cu, Mn, and Zn

“…Plants can be used for phytoremediation in different ways ( Figure 1) including removal of contaminants from water and aqueous waste streams in constructed wetlands or filtering pollutants through the root systems of hydroponically cultivated plants, a process called rhizofiltration (Chandra and Yadav, 2011;Valderrama et al, 2012). Deep-rooted species, such as trees, can be used to provide a hydraulic barrier and plume containment through evapotranspiration, creating an upward water flow in the root zone and preventing the spread of contamination (Dominguez et al, 2009).…”

“…The amphibious water plant Crassula helmsii can also hyperaccumulate Cu (Kupper et al, 2009). Based on the Cu accumulation of Azolla filiculoides (6013 μg g −1 ), this species can be regarded as a potential phytoremediation organism with high potential for cleaning water polluted with Cu (Valderrama et al, 2012). In another study, Liu et al (2010a) compiled information about 19 wetland plant species and concluded that the selection of appropriate plant species in constructed wetland is crucial for the improvement of metal removal efficiency.…”

Microcosm Investigation on Differential Potential of Free Floating Azolla Macrophytes for Phytoremediation of P-controlled Water Eutrophication

“…These results showed that P-removal from solutions is due to plant P-uptake, and removed [P]s are accumulated into plants. Because the total pollutant extraction is the product of biomass and tissue concentration (Comis, 1998;Valderrama et al, 2013), hence the success of phytoremediation mainly depends on the plant growth rate and bioaccumulation ability. As the tested Azolla plants showed both these characteristics, therefore, Azolla macrophytes might be the effective plants for phytoremedation of P-eutrophicated waters.…”